Dude this is just wrong. 18k hands says nothing. I'm not here to argue with you, take the advice or leave it but if we are talking postflopstats 18k is just not a big sample. Also winnings. You could assume if you were a winning player or not but that's it. 18k is affected a lot by variance, check the tool I've send you earlier. As for preflop stats yeah you could say 18k is a decent sample. But then again these stats are so irrelevant most of the time that it doesn't matter. Atleast for your own game. Unless you have massive leaks over there but as stated you have some game knowledge. 100k hands is a samplesize you can start working with. Alltough even that sample is still affected by variance. Atleast here we can somewhat deduct winrates. True winrates can be see at around 500k hands, just for some perspective.
As for 52 cards, yeah lol, that also makes 259890 combos of hands.
I might sound harsh here, wich I don't want to, so please take this with a grain of salt. You might have improved analyzing a sample of 4k hands and getting better for 2 reasons A. You were bad overall and improved trough actually thinking about the game B. Luck, the stats were just pointing in the right direction.
And don't get me wrong, improving is good, by whatever reason, but going crazy over 18k hands is not good.
Sigh... it is better to be a mathematician than to just look on the internet and quote them. Your figure is too short by the way... it is 10 times larger: 2,598,960. The reason for that is that you just quoted it. How about you copy and paste next time?
Now lets put some actual mathematics into this and some common sense:
10200 straights right? That's funny, because the last time I checked there were 8 straights.
8 seems a little lower than 10200 doesn't it? Are you really concerned about your jack of clubs not being as good as you opponent's jack of spades? K-9 is one straight and if that is what you both have, then you share the pot. There are not different versions of it because of suit unless you include straight flush.
Here's another pure common sense thing. Have you actually thought that unless there are 3 of the same suit on the table, then suit does not even come into it AT ALL! Do you even realize how much of your original figure is reduced by that fact alone? Drastically - that is how much. Yes, the only types of hand that takes into account suit are the flush types. If there ain't 3 of the same suit you ain't gonna get beat by flush!
1,098,240 types of pairs right?? The last time I checked there are 13 different types of pair. Of course the kicker comes into play... so you have another 12 possibilities on top of that. If you are playing for a pair on the table then you may just as well consider that you have high card anyway - so that is irrelevant (everyone knows it is as good/ bad as high card). Even if you were to waste your time going through all the different combinations of kickers someone could be holding when playing for a table pair, do you honestly think it will come to over 1 million?
...and who is going to be betting hard on a pair anyway??
Just to top this all off and pinpoint exactly how simple this is (and why you have absolutely no need for the strange website you linked to):
After the flop, with you and one opponent, you know 5 cards out of that pack of 52. You know that 3 of them your opponent has as well. If you are now holding a set of 10s there is a very limited way in which your opponent can win. On a rainbow board, are you going to fold if they go all-in? Do you seriously think anyone is (especially if the opponent is a loose player with VPIP 80)? Indeed there could be a king or ace on there but that could mean your opponent is going for 2 pairs or even TOP pair (super aggressive)!
All you need to know is that you are very likely to win... you do not need a head filled with mathematical nonsense.